Study On The Mechanism Of Torularhodin In Intervention Of Obesity Induced By High Fat

Obesity is considered to be a global health problem,which can increase the risk of chronic metabolic diseases,including chronic inflammation,diabetes,hypertension,etc.,leading to a wide range of social and economic burdens,which need to be solved urgently worldwide.Although genetic and environmental factors are considered to be the main causes of obesity,the root cause should be attributed to the imbalance between dietary intake and energy consumption.At present,the main way to lose weight is to reduce energy intake and increase physical exercise.However,due to rich food and less free time,it is very difficult for most people.Therefore,it is necessary to find more effective and simpler strategies to treat obesity.Internationally,therapeutic intervention through weight-loss drugs is one of the options for effective treatment and management of obesity.However,there are only a few approved anti-obesity drugs on the market,but there are also side effects and uncertain risks.Therefore,it is of great practical significance to find safe and effective functional components from natural foods to prevent obesity and related metabolic diseases.In this paper,Torularhodin produced by the yeast screened and optimized by our laboratory was used as natural functional raw material.Firstly,through the exploration of carrier form,it was found that three different physical forms of corn oil solvent,corn oil nanoemulsion spray dried powder and corn oil nanoemulsion alginate gel could affect the distribution of torularhodin in the gastrointestinal tract and thus affect the metabolic results,among which the corn oil nanoemulsion alginate gel had the best biological effect.Then,the CDMN continuous colonic fermentation system was used to simulate in vitro,and the beneficial effects of torularhodin on gut microbiota and metabolites were confirmed.Then,the obesity mouse model induced by high-fat diet was established.Proteomics,metabolomics and microbiomics were used to explore the mechanism of torularhodin intervention on obesity from different perspectives,such as changing gut microbiota,increasing fat metabolism and reducing the expression of proteins related to inflammatory response.The main contents are as follows:(1)Aiming at the problems of unstable and easy oxidation,hydrophobic and low absorption rate of torularhodin,the effects of three carrier forms on storage stability and absorption and metabolism of torularhodin in digestive tract were firstly studied,namely:(1)Corn oil loaded with torularhodin(T-oil),(2)OSA-starch mediated torularhodin corn oil nanoemulsion spray drying powder(T-EP),(3)torularhodin corn oil nanoemulsion alginate gel(T-EPA).The results showed that in terms of stability of torularhodin,T-oil was the most stable,followed by T-EPA,but T-EPA had the best sustained release.In digestive tract delivery and absorption,T-EPA carrier form has more advantages.It can target the acid intolerant,poor stability of torularhodin to the colon for slow release,and may play its health function in the colon by interacting with the microbiota.(2)The CDMN continuous colonic fermentation system was used to simulate the effects of torularhodin on human gut microorganisms and their metabolites under anaerobic conditions in vitro with the samples of torularhodin in the form of T-EPA carrier and corn oil nanoemulsion alginate gel EPA without torularhodin.It was found that compared with the EPA control group,the concentration of propionic acid in T-EPA group containing torularhodin was significantly increased,and the concentration of butyric acid and valeric acid were also increased.It can be speculated that torularhodin directly or indirectly promoted the metabolism of human gut microorganisms to produce SCFAs such as propionic acid and butyric acid.The analysis of the diversity of the bacterial community showed that torularhodin affected the composition of the bacterial community,and the longer the time,the more obvious the effect.The identification and analysis of key microorganisms showed that torularhodin could up-regulate the abundance of beneficial microbiota such as short-chain fatty acid production and cholesterol degradation,and down-regulate the abundance of harmful microbiota related to obesity and inflammation.(3)Long-term high-fat diet can induce significant weight gain in mice,resulting in obesity,dyslipidemia,impaired glucose tolerance,insulin resistance,systemic inflammation,and LPS closely related to inflammation is also significantly increased.Microscopic observation of H&E stained sections of liver and white adipose tissue further confirmed the presence of severe lipid accumulation in liver and adipose tissue.Replenishment of high dose(about 40mg/Kg body weight/day)of torularhodin in high-fat diet can effectively inhibit obesity induced by high-fat diet,and can reduce obesity related dyslipidemia,glucose intolerance,insulin resistance and systemic inflammation.Reduction of lipid accumulation has also been observed in liver and white adipose tissue.The beneficial effects of torularhodin were better than the equivalent dose of the positive control lycopene,while the effect of torularhodin at lower doses(approximately equivalent to 10mg/Kg body weight/day)was not significant.(4)Using proteomics and metabolomics,it was demonstrated that torularhodin increased fat degradation and cholesterol secretion,and decreased lipid absorption by regulating the expression of proteins related to PPARα signaling pathway,especially increasing the levels of PPARα,CYP7A1 and CPT1 a and decreasing the level of SLC27A4.Thus,it can treat obesity and related dyslipidemia caused by high-fat diet.Increased expression of apolipoproteins,especially Apo A-1 and Apo A-II associated with HDL-C,is also beneficial to treat dyslipidemia and its function of lowering cholesterol and reducing fat accumulation.Many proteins associated with the anti-inflammatory function of torularhodin are also PPARα target genes.Therefore,PPARα signaling pathway may be the basic mechanism by which torularhodin ameliorates dyslipidemia,anti-liver inflammation,and reduces obesity and other health benefits.(5)Studies on the intestinal tract showed that torularhodin intervention could help restore the damage of intestinal barrier caused by high-fat diet and increase the SCFAs reduced by high-fat diet.Analysis of the gut microbiota found that torularhodin intervention could reverse the increase in Firmicutes/Bacteroidota ratio caused by high-fat diet.At the generic level,it is identified that high-fat diet can reduce the beneficial bacteria groups associated with the production of SCFAs,inhibition of inflammation,and promotion of lipid metabolism,such as Akkermansia,Lactobacillus,Eubacterium＿coprostanoligenes;at the same time,it can increase the harmful bacteria Faecalibaculum,Lachnospiraceae and Turicibacter,which are related to the synthesis of fatty acids,promoting inflammation and damage to the intestinal barrier.These changes caused by high-fat diet could be reversed by torularhodin intervention.Spearman correlation analysis between key microorganisms and phenotypes,differentially expressed proteins,metabolites further proved that torularhodin could reverse the adverse changes of gut microbiota caused by high-fat diet,treat obesity and related health problems such as dyslipidemia and inflammation caused by high-fat diet...